The Note: Clinton, Sanders Spar Over Electability

— -- NOTABLES

--A SCUFFLE IN SIN CITY: All three Democratic candidates met onstage in Las Vegas last night, and while each took turns attacking Republicans, Bernie Sanders and Hillary Clinton also saved subtle jabs for each other. The two sparred over the issue of who would fare best in a general election matchup, ABC’s LIZ KREUTZ and MARYALICE PARKS note. Earlier this week, Clinton urged Democratic Party voters to consider electability when making their choice. In Nevada she said voters will soon be choosing a president “who can get the job done, and not just on a few issues, but on all the complex challenges we face.” She added that she has been raising money for Democratic state parties. "Right now I am not only running for president but raising millions of dollars for our state parties,” she said.  Sanders, on the other hand, conjured images of his large crowds from the trail and took swipes at Clinton. “Our job should not be simply to be running around the country making money from the wealthy. Our job should be to bring working people together in basketball arenas and football arenas by the tens of thousands, to answer their questions, to mobilize them so we have the fighting force we need to transform this country.” 

--ANALYSIS -- ABC’s RICK KLEIN: Happy birther days, all over again. Donald Trump’s decision to question – just citing others’ concerns, in typical Trump fashion – Ted Cruz’s eligibility for the presidency is a Trumpian sneak attack in that it’s not at all sneaky. In fact, it’s designed to explicitly undermine Cruz with the kinds of voters who are showing signs of settling on him. (And Cruz is learning anew how few friends he has among his colleagues with Rand Paul and even John McCain – himself born outside the United States – saying they’re not sure if he can run for president, either.) It all speaks to the threat Cruz poses in Iowa and well beyond, and it can’t be quieted with a birth certificate. Cruz’s vow to not engage in fights with his rivals will be tested even more than his constitutional eligibility these last few weeks before voting starts.

--MIKE HUCKABEE TALKS TO THE NOTE ABOUT COMPLETING THE 'FULL GRASSLEY' IN IOWA. Republican presidential candidate Mike Huckabee will hit the magic number today: 99. With no fewer than six separate campaign events (from Sigourney to Urbandale), Huckabee will have visited every single county in the Hawkeye State since he announced for president last May. "We methodically and systematically planned our schedule so that we would get to all counties," Huckabee told The Note. "We didn't just do a drive through -- we actually did town halls." He added, "I don't think anybody is going to say we're low-energy." The former Arkansas governor who won the Iowa caucuses as a presidential candidate in 2008 but who is lagging behind many of his competitors in the polls this year said he isn't putting much stock in the latest numbers. "The pundits who make these predictions at this point are wrong every four years," he said. Recalling 2008, he said: "I can’t think of anybody that said we were going to win. The question was: Would we come in a close or distant second? We didn't just win, we won the most votes in the history of the Iowa caucuses."

--ON CRUZ: When asked about the new questions being raised about Canadian-born Sen. Ted Cruz's eligibility to be president, Huckabee said: "I have not dealt with it at all. If that was going to be challenged, it would have been when he was elected to the Senate," Huckabee said in an interview with ABC News yesterday. Huckabee said the biggest issue for the Cruz, who currently sits at the top of the polls in Iowa, is whether he changes his views on issues based on where he happens to be campaigning that day. "If you hear me speak in Waukee, Iowa," Huckabee said. "It's the same as when I speak in Washington."

--ON IOWA: Looking ahead to the state's Feb. 1 caucuses, Huckabee pronounced himself "very optimistic that we still have a shot at this." His prospects beyond Iowa, he said, would be based on "where things cluster" in the final caucus standings. "We also know that if we don't come up near the top, then we have a hard time continuing," he said.

TODAY ON THE TRAIL with ABC’s RYAN STRUYK: Today Donald Trump is going into enemy territory, holding a rally tonight in Democratic hopeful Bernie Sanders’ home state of Vermont, where he may have sold more than ten times too many tickets for the venue. Ted Cruz will spend the afternoon and evening with four events in Iowa on his bus tour, where he’s favored to win the state. Ben Carson is also in the Hawkeye State with three town hall meetings. Rand Paul, Rick Santorum and Mike Huckabee are also in Iowa today. Marco Rubio, meanwhile, is aiming to pick up momentum in New Hampshire with a house party and a town hall today. Jeb Bush is also hosting two town halls there and John Kasich has three events. On the Democratic side, fresh off a series of speeches from the three candidates in Nevada last night, Hillary Clinton will rally her Asian American and Pacific Islander supporters in California. Her husband former President Bill Clinton is back on the trail today with two organizing events in Iowa this afternoon after his first. Minnesota Senator Al Franken is also hitting the campaign trail for the former Secretary of State, with four appearances in New Hampshire. Martin O’Malley has two events – one in Nevada and one in Iowa.

FIRST ON ABC: NEW RNC AD AIMS TO SHOWCASE DIVERSITY IN GOP. The Republican National Committee is set to run a series of ads before and during next week’s GOP debate highlighting a new effort to attract diverse voters in 2016, ABC’s SHUSHANNAH WALSHE reports. ABC News got a sneak peek at the “Where You Lead, Others Will Follow” ad campaign featuring a diverse group of Republicans that are already active in the party. The series features a former prostitute; a 9/11 firefighter in The Bronx, New York; the son of Haitian immigrants and a mentor from Queens, New York; a mother of a child with autism from Tampa, Florida; and a first generation Hispanic American college student from Pueblo, Colorado. Vallerie, the former prostitute, says in the ad her mother passed away when she was jail and she was “not allowed to go to her funeral.” “I had this epiphany and realized I didn’t need to live like this,” she said, adding she has “already started organizing within my neighborhood.” The RNC says the effort is an initial $300,000 ad buy, which includes television commercials before and during Thursday’s South Carolina debate and a digital buy for the first quarter. The effort also includes an Instagram account and a new website featuring the series. http://abcn.ws/1O66g1V

YESTERDAY ON THE TRAIL

DONALD TRUMP WANTS TED CRUZ TO ‘GO BEFORE A JUDGE’ TO CLEAR UP CITIZENSHIP ISSUE. In an interview with CNN on Wednesday, Trump, the Republican presidential frontrunner, encouraged Cruz, his GOP rival, to go to federal court “immediately, like tomorrow” and ask for a declaratory judgment about whether he is a naturally born citizen of the United States and therefore constitutionally eligible to be president. Trump cast such a move as “for the good of Ted.” ABC’S JENNIFER HANSLER and PAOLA CHAVEZ note Trump’s stated doubts seem to differ from his opinion in September when he was asked about Cruz’s eligibility for the White House. “I hear it was checked out by every attorney and every which way and I understand Ted is in fine shape,” Trump told ABC News at the time. http://abcn.ws/22M2PoD

NOTED: CRUZ SAYS HIS RECORD IS STRONGER THAN TRUMP'S. Republican presidential candidate Ted Cruz seems unfazed by the increasing attacks from his frontrunner opponent Donald Trump. "I think my record is stronger than his," Cruz said in an interview with ABC News’ Tom Llamas Wednesday. "I think my record is stronger than any other Republican candidate in the field." Cruz and Trump are battling for two key early voting states -- New Hampshire and Iowa. In a mid-December Iowa poll, Cruz lagged Trump by only 1 percent. ABC’S JESSICA HOPPER and JENNIFER HANSLER noted when asked whether Trump should view him as a threat, Cruz not only refused to engage, but called on Trump to stay silent as well. http://abcn.ws/1TF0wh9

CONSTITUTIONAL SCHOLARS EXPLAIN WHY TED CRUZ IS ELIGIBLE TO BE PRESIDENT. Donald Trump says questions about whether Ted Cruz is eligible to be President of the United States could become a “big problem” for the Canadian-born Republican candidate. But among legal scholars, there’s a consensus: He’s eligible to occupy the Oval Office. The Texas senator, who was born in Calgary, Canada, to an American mother, has been widely viewed as meeting the “natural born citizen” requirement of the United States Constitution. ABC’S RYAN STRUYK has more on why most legal experts agree. http://abcn.ws/1JYd3XB

JOHN KASICH JUST HELD HIS 50TH NH TOWN HALL. Ohio Governor John Kasich held his fiftieth town hall in New Hampshire Wednesday night, more than any other candidate in the presidential race. And to celebrate, he brought a cake, ABC’s BRAD MIELKE notes. “Isn’t that cool?” he said of the American flag design, encouraging supporters to come up and grab a slice. “It’s really neat.” Kasich finds himself among a swarm of Republicans pinning their presidential hopes on the Granite State. Jeb Bush recently sent several of his Miami staffers to New Hampshire, and Chris Christie has spent the vast majority of his campaign in the state. http://abcn.ws/1RbnuP3

2016 PRESIDENTIAL CANDIDATES REACT TO ALLEGED NORTH KOREAN H-BOMB TEST. North Korea announced Tuesday night that it had conducted a successful hydrogen bomb test. Although the detonation has not yet been confirmed, the possibility that North Korea has intensified its nuclear capability has evoked strong reactions not only from the global political community, but also from 2016 presidential candidates. ABC’S JENNIFER HANSLER and PAOLA CHAVEZ have more. http://abcn.ws/1Pf3J35

IN CASE YOU MISSED IT

HOW TINY TURTLES AND A BABY JESUS ENDED UP IN JEB BUSH'S POCKET. It was close to 9 a.m. Republican presidential candidate Jeb Bush was in a local New Hampshire eatery, engaging in some old fashioned "retail politicking." He encountered Sherrie Morrow of Kittery, Maine and her son Zacharie, 13. They chatted with Bush and when they left, Zachary left with this: It’s a small metallic turtle. With it, he left Zacharie a piece of advice, a slogan that’s become his campaign’s adage: “Slow and steady wins the race.” It turns out the parting gift was not entirely unique. ABC’S CANDACE SMITH reports Bush later showed reporters, he has other tiny turtles lining his pockets, just for occasions like these. http://abcn.ws/22LgLiU

WHO’S TWEETING?

@JesseFFerguson: NEWS: Congressional Black Caucus Chair G.K. Butterfield (NC) Backs @HillaryClinton in new Grio Op-Ed http://thegrio.com/2016/01/07/g-k-butterfield-endorses-hillary-clinton/ …

@TheBrodyFile: .@TheBrodyFile Exclusive: @marcorubio To Unveil "Faith" Ad in Iowa This Weekend. Watch here first. http://blogs.cbn.com/thebrodyfile/archive/2016/01/06/brody-file-exclusive-marco-rubios-new-faith-ad-in-iowa.aspx … #2016

@VVFriedman: On the subject of Marco Rubio's boots: Shoe's on the other foot now, boys...http://nyti.ms/1RuORlP 

@nycjim: Better than coffee: 2016 campaign videos delivered with 90s sitcom laugh tracks. http://mashable.com/2016/01/07/campaign-videos-90s-sitcom-laugh-tracks/?utm_cid=hp-hh-sec#lWtcjp.HkkqF …

@continetti: Positioning for @realDonaldTrump cabinet has begun http://www.usatoday.com/story/opinion/2016/01/06/trump-rubio-bush-florida-economy-rick-scott-column/78321590/?wpmm=1&wpisrc=nl_daily202 …